In order to assess the efficiency of use of mulberry leaf by the hybrid Băneasa Super of Bombyx mori larvae, during a series of growth, some determinations were made related to the nutritional value and digestibility of the three varieties of leaf. The results showed that the advanced vegetation stage and during each period of growth of silkworm larvae, the mulberry leaf undergoes an aging process, translated by the quality decrease regarding the chemical composition. According to this aspect, in most mulberry leaf nutrients other than cellulose, a continuous decrease in digestibility was observed throughout the growing period. The results show that for the Bombyx mori larvae, from mulberry leaf, an average of 10.38 grams of dry matter is ingested and 5.92 grams of digested dry matter is required for each gram of silky coating, which indicates an efficient conversion into silk of 9.65% of the intake (ECI), and 17% of digest (ECI).